Process of preparing fatty compounds



Patented Feb. 12, 1952 P-RQGESS OFPREPARING FATTY CQMPORUN'DS Arthur I. Gebhart, Union,

and- John. Ross,

Ramsey, N.. J'., assignors to Colgate-Palmolive- Peet Company, Jersey City, N. .L, a corporation of Delaware No Drawing; Application March 3, 1948-, Serial No. 12,898.-

7" Claims. (Cl. 260-413) This invention relates toa process for preparing: fatty compounds having an odd number of carbon atoms in the molecule. More particularly; the invention pertains to the production of relatively high molecular weight fatty aldehydes andfor fatty acids and compounds: derived therefrom containing an odd number of carbon atoms in. the molecular structure.

Among the large. number of fatty acids. found in natural oils. and. fats, it is known that almost all are straight chain compounds containing an even number of carbon atoms. The odd-hum bered fatty aldehydes and fatty acids, however, have certain physical and chemical characteristics which distinguish, them from the. correspending even-numbered compounds, and for some purposes these odd-carbon compounds. are preferred to the even-numbered compounds... For instance, in the biochemical field: it. has; b en reported that a synthetic fat prepared from the odd carbon fatty acid margarid. for example was less ketogenic than ordinary fat, and that such synthetically prepared fat. was a useiulnutriment: for human diabetics. (Rte Biochemistry of the Fatty Acids by W. R. Bloor, 1943 Ed. Chapter Similarly, where the melting pointof the. fatty acid is. desired to be. kept as low as, possible, use may be made. of the odd-numbered acids boas..-- much. as the melting point of an odd-numbered acid is somewhat lower than that. of the. next. lower even-numbered acid as. wellv as the next. higher even-numbered acid.

The odd-numbered fatty aldehydes and fatty acids have not been used to any great extent heretofore, principally because they have. been diificult and expensive to prepare by prior known methods. In accordance with the present. invention a comparatively simple and efficient method is provided for preparing odd-numbered fatty compounds from olefinic hydrogarbons. Briefly, the invention comprises subjecting appropriate olefinic hydrocarbon material to a selective oxidizing action to cause hydroxylation of the olefinic bond and formation of a saturated dihydroxy' compound of the Vic-glycol type. Thereafter this dihydroxylated compound is further oxidized so as to bring about a cleavage between the contiguous carbons of the ta ta grouping and formation of the desired odd-carbon fatty aldehyde or corresponding fatty acid or aldehyde-acid compound.

While some use has been made of this vic- 2 glycol cleavage reaction in testing for the presence of contiguous hydroxyl groups and hydroxyl and amino groups, no one. heretofore, insofar as We are aware, has devised a practical method of utilizing such a reaction step in a process for preparing odd-carbon fatty compounds from olefins.

In accordance with the. present invention, useful fatty compounds, containing an. odd number of carbon atoms, and preferably ranging upwards from seven to twenty-three or higher, are prepared from mono-olefins of normal or branched chain structure. These olefins may be represented by the general formula wherein R1 and R represent alkyl groups, or chains of which one. group. atleast, as represented. by R1 or R2, contains an odd number of carbons, and not less than seven. This; mono-olefinic material is subjected to a selective oxidizing action whereby the olefinic bond is. hydroxylated producing a vie-glycol compound. The resultant d-ihydroxylatedproduct is then further oxidized to cause cleavage of the same between the con,- tiguous hydroxylated carbon atoms and formation of an odd-carbon fatty aldehyde as one of the fragments. This odd-carbon fatty aldehyde upon additional oxidizing. treatment is readily converted to the corresponding odd-carbon fatty acid.

While. it. is. generally preferred to use normal aliphatic mono-olefins. as starting materials, in practicing the present invention, it will be ape preciated that other suitable starting materials may be. used. For example, cracled parafiin dis.- tillate, as obtained during the cracking of hy drocarbons and containing a high proportion of mono-olefinic compound may be. employed as a source of. olefinic material, the. distillate being used with or without pretreatment. Suitable mono-olefins which are useful for carrying out.

.the invention are hexadecene-l, hexadecene-a,

dodecene-l, dodecene-B, tridecenel,pentadecene 2, octadecene-l, and similar homologous. olefinic compounds. Suitable mixtures. of these olefinic materials may also be used where the. production of mixed odd-carbon fatty compounds is desired.

The following examples will serve to illustrate how the process of the invention may be practiced, it being understood that the same is not restricted thereto.

' Example I A mixture of 38 ml. ofglacial acetic acidand 25 ml. of acetic anhydride is heated to 40 C. and r 12 ml. of a 30% aqueous solution of hydrogen peroxide added, the addition being carried out over a period of about thirty minutes, and the acetic acid-anhydrlde mixture constantly stirred and maintained at a temperature of from 38 to 40 C. After letting the mixture stand overnight at room temperature, grams of hexadecene-l is added and the mixture heated to from 85 to 90 C. until the hydrocarbon dissolves and the reaction mixture becomes homogeneous. After the solution is maintained at this temperature for about fifteen minutes it is then left to stand overnight at 35 C. Upon diluting the resultant reaction mixture with four volumes of water and extracting with ether a solid material is obtained, which after saponification with potassium hydroxide, acidification and extraction with ether, yields almost the theoretical amount of dihydroxy-hexadecane as a white solid.

A solution containing 13.8 grams of this dihydroxy-hexadecane in 100 ml. of ethyl alcohol is treated with a solution comprising 12.5 grams of periodic acid in 25 ml. of ethyl alcohol, and the mixture allowed to stand at room temperature for about twenty minutes. Dilution of the resultant reaction mixture with water and extraction with ether yields the fatty aldehyde pentadecanal which is insoluble in the aqueous solution, being readily separated from the formaldehyde formed which dissolves in water. Oxidation of this higher fatty aldehyde by heating the same to about 85 to 95 C. in a mixture containing 7 ml. of 30% H202 and 35 ml. of acetic acid, allowing the mixture to stand overnight at 35 C., and diluting the resultant reaction mixture with water and extracting with ether. yields pentadecanoic acid as a White crystalline solid.

tion of peracetic acid prepared by adding hydro en eroxide to a mixt re of acetic acid and acetic acid anhvdride, as in Example I, and the res ltant mixture eated to 90 C. whereupon the h rocarbon d ssolves and a clear homo eneous sol tion res lts. Thereafter the solution is maintained at this tem erature for about t enty minutes and then left to stand overnight at 35 C. Unon diluting the resultant reaction mixture with four volumes of water and extracting with ether 2. solid product is obtained, which after sa onification with potass um hydroxide, acidification and extraction with ether, yields practically the theoretical amount of dihydroxy octadecane as a white solid.

A solution containing 14 grams of this dihydroxy octadecane dissolved in 100 ml. of ethyl alcohol is treated with a solution comprising 12.5 grams of periodic acid dissolved in 25 ml. of ethyl alcohol, and the resultant mixture allowed to stand for twenty minutes at room temperature. Dilution of this reaction mixture with water and extraction with ether, as in Example I, yields the fatty aldehyde heptadecanal. This fatty aldehyde is then oxidized to the corresponding oddcarbon fatty acid by adding a solution comprismg 7 ml. of 30% hydrogen peroxide and 35 ml.

of acetic acid, heating the mixture to from 85 to 90 C. for a few minutes, and then allowing it to stand overnight at 35 C. The resultant mixture upon dilution with water and extraction with ether yields heptadecanoic (margaric) acid. as a white crystallinesolid. I

4 Example III This example illustrates the process as carried out using a branched-chain olefin as starting material, and wherein R1 of the formula R1=Rz contains an odd number of carbons, part of which is included as a side chain or branch structure.

To a peracetic acid solution, prepared as described in Example I, is added 6.9 grams of 5- ethyl nonene-2 and the mixture heated to 90 C. when the hydrocarbon dissolves and the reaction mixture becomes homogeneous. The solution is maintained at-this temperature for about thirty minutes and then left to stand over night at 35 C. Upon diluting the resultant reaction mixture with several volumes of water and extracting with ether a solid product is obtained, which after saponiflcation with potassium hydroxide, acidification and extraction with ether, yields 7.6 grams of 5-ethyl dihydroxynonane. This represents a yield'approximating 90% of the theoretical value.

A solution containing 7.5 grams of this 5-ethy1 dihydroxynonane dissolved in ml. of ethyl alcohol is treated with a solution comprising 9.2 grams of periodic acid dissolved in 20 ml. of ethyl alcohol, and the resultant mixture allowed to stand for thirty minutes at room temperature. Dilution of the resultant reaction mixture with water and extraction with ether, as in Example I, yields the fatty aldehyde 3-ethyl heptanal. This fatty aldehyde is then oxidized to the corresponding odd-carbon fatty acid by adding a solution comprising 6 ml. of 30% hydrogen peroxide and 25 ml. of acetic acid, heating the mixture to from to C. for a few minutes, and then allowing it to stand overnight at 35 C. The resultant reaction mixture upon dilution with water and extraction with ether yields 3-ethyl heptanoic acid.

may be used. In some instances potassium permanganate (KMnO4) may be employed as the oxidizing agent to effect hydroxylation of the olefiinic compounds. Likewise, other oxidizing com'- pounds other than periodic acid may be used, such as suitable mixtures of lead tetraacetate to further oxidize and bring about cleavage of the contiguous hydroxylated carbons.

The invention has been described with respect to certain specific examples and preferred methods, but it will be appreciated by those skilled in the art that suitable variations and modiflcations of the invention may be made without departing from the principles and real spirit of the invention.

What is claimed is:

1. A unitary process of preparing fatty acid compound containing an odd number of carbon atoms in the molecule and numbering at least 7, which comprises dissolving in a solution of peracetic acid in acetic acid a mono-olefin of the formula wherein R1 and R2 represent alkyl groups of which one group at least contains an odd number of carbon atoms and not less than 7, reacting said mono-olefin with said peracetic acid to carbon having a'hydroxyl group attached to each of the contiguous and previously unsaturated carbon atoms of said olefin, selectively oxidizing said dihydroxy saturated hydrocarbon 'by treat ing the same with periodic acid to cause cleavage between said contiguous hydroxylated carbons and form thereby a fatty aldehyde containing an odd number of carbon atoms in the molecule, further selectively oxidizing said fatty aldehyde by dissolving the same in a solution of peracetic acid in acetic acid to form the corresponding odd-numbered carbon fatty acid, and separating and recovering the resultant odd-numbered fatty acid compound.

2. A unitary process of preparing a fatty aldehyde containing an odd number of carbon atoms in the molecule and numbering at least 7, which comprises reacting a mono-olefin of the formula wherein R1 and R2 represent alkyl groups of which one group at least contains an odd number of carbon atoms and not less than '7, with peracetic acid in acetic acid solution to selectively oxidize said mono-olefin and form a hydroxysubstituted saturated hydrocarbon as a reaction product, hydrolyzing the same to yield a dihydroxy saturated hydrocarbon having a hydroxyl group attached to each of the contiguous and previously unsaturated carbon atoms of said olefin, selectively oxidizing said dihydroxy saturated hydrocarbon by treating the same with periodic acid to cause cleavage between said contiguous hydroxylated carbons and form thereby a fatty aldehyde containing an odd number of carbon atoms in the molecule, and separating the resultant fatty aldehyde containing an odd num ber of carbon atoms of at least '7 in the molecule.

3. In a process of preparing fatty compounds selected from the group consisting of fatty aldehydes and fatty acids, said compounds containing an odd number of carbon atoms in the molecule and numbering at least 7, the steps which comprise dissolving in an organic per acid solution a mono-olefin of the formula wherein R1 and R2 represent alkyl groups of which one group at least contains an odd number of carbon atoms and not less than 7, reacting said mono-olefin with said per acid to selectively oxidize said mono-olefin and form a hydroxy-substituted saturated hydrocarbon as a reaction product, hydrolyzing the same to yield a dihydroxy saturated hydrocarbon having a hydroxyl group attached to each of the contiguous and previously unsaturated carbon atoms of said olefin, selectively oxidizing said dihydroxy saturated hydrocarbon by treating the same with periodic acid to cause cleavage between said contiguous hydroxylated carbons and form thereby a fatty aldehyde containing an odd number of carbon atoms in the molecule, and recovering said fatty compound.

4. A unitary process of preparing a fatty acid compound containing-an odd number of carbon atoms in the molecule and numbering at least 7, which comprises dissolving in a liquid organic per acid solution a mono-olefin of the formula which one group at least contains an odd numher of carbon atoms and"'not"'1es's"than 7, reacting said mono-olefin with said per acid to selectively oxidize said mono olefin and form a hydroxy-substituted saturated hydrocarbon as a reaction product, hydrolyzing the same to yield a dihydroxy saturated hydrocarbon having a hy droxyl group attached to each of the contiguous and previously unsaturated carbon atoms of said olefin, selectively oxidizing said dihydroxy saturated hydrocarbon by treating the same with periodic acid to cause cleavage between said contiguous hydroxylated carbons and form thereby a fatty aldehyde containing an odd number of carbon atoms in the molecule, further selectively oxidizing said fatty aldehyde to form the corresponding odd-numbered carbon fatty acid, and separating and recovering the resultant oddnumbered fatty acid compound.

5. A process of preparing pentadecanoic acid from olefins which comprises subjecting hexadecene-l to selective oxidation by reacting the same with a peracetic reagent of a mixture of acetic acid, acetic anhydride, and hydrogen peroxide to form a hydroxylated reaction product, hydrolyzing said reaction product to form dihydroxy hexadecane wherein a hydroxyl group is attached to each of the contiguous and previously unsaturated carbon atoms, selectively oxidizing said dihydroxy hexadecane by treating the same with periodic acid to cause cleavage between said contiguous hydroxylated carbons and form thereby the fatty aldehyde pentadecanal, further oxidizing said fatty aldehyde to form pentadecanoic acid, and separating and recovering said pentadecanoic acid.

6. A process of preparing heptadecanoic acid from olefins which comprises subjecting octadecene-l to selective oxidation by reacting the same with a peracetic reagent of a mixture of acetic acid, acetic anhydride, and hydrogen peroxide to form a hydroxylated reaction product, hydrolyzing said reaction product to form dihydroxy octadecane wherein a hydroxyl group is attached to each of the contiguous and previously unsaturated carbon atoms, selectively oxidizing said dihydroxy decane by treating the same with periodic acid to cause cleavage between said contiguous hydroxylated carbons and form thereby the fatty aldehyde heptadecanal, further oxidizing said fatty aldehyde to form heptadecanoic acid, and separating and recovering said heptadecanoic acid.

7. A process of preparing 3-ethy1 heptanoic acid from olefins which comprises subjecting 5- ethyl nonene-Z to selective oxidation by reacting the same with a peracetic reagent of a mixture of acetic acid, acetic anhydride, and hydrogen peroxide to form a hydroxylated reaction product, hydrolyzing said reaction product to form 5- ethyl dihydroxy nonane wherein a hydroxyl group is attached to each of the contiguous and previously unsaturated carbon atoms, selectively OX- idizing said 5-ethyl dihydroxy nonane by treating the same with periodic acid to cause cleavage between said contiguous hydroxylated carbons and form thereby the fatty aldehyde 3-ethyl heptanal, further oxidizing said fatty aldehyde to form 3- ethyl heptanoic acid, and separating and recovering said 3-ethyl heptanoic acid.

ARTHUR I. GEBHART. JOHN ROSS.

(References on following page) REFERENCES CITED UNITED STATES PATENTS Name Date Miles Mar. 9, 1948 Number OTHER REFERENCES 1 D. Swern et aL, "Hydroxylation and epoxida- 8 tion of some l-oleflns with per acids, Journ. Amer. Chem. Soc. 68, pages 1504-7 (1946).

R. Criegee, The specificity of oxidizing agents: A comparison of the oxidizing action of lead tetraacetate and periodic upon polyhydroxy compOunds. 29 Chem. Abst. 6820-6821, October 20, 1935.

C. C. Price et a1., Kinetics of the periodate oxidation of 1-2-g1yco1s, Journal Amer. Chem. Soc. 64, 552-4 (1942) 36 Chem. Abst. 2528, May 10, 

1. A UNITARY PROCESS OF PREPARING FATTY ACID COMPOUND CONTAINING AN ODD NUMBER OF CARBON ATOMS IN THE MOLECULE AND NUMBERING AT LEAST 7, WHICH COMPRISES DISSOLVING IN A SOLUTION OF PERACETIC ACID IN ACETIC ACID A MONO-OLEFIN OF THE FORMULA 